Prostaglandins

Abbreviation: PG. A general term for monocarboxylic acids with 20 carbon atoms and one five-membered ring, which are widely distributed in the body and exhibit a variety of physiological activities. Research on prostaglandins began in 1930, when P. Kurzock and CC Lieb discovered that human semen has the ability to contract or relax uterine muscles. US von Euler and others isolated the organic acid components soluble in organic solvents and named them prostaglandins. These have a basic skeleton of prostanoic acid, which is formed in the body by oxidatively forming a five-membered ring from arachidonic acid or eicosapentaenoic acid, and are classified into groups A to J depending on the oxygen atom and double bond in the five-membered ring, and there are also groups 1 to 3 depending on the number of double bonds in the side chain. These are combined and written as PGE, PGF ₂ , etc. Furthermore, when there is a hydroxyl group at the 9th position, the stereochemistry is classified as α or β, and about 20 types are known. The physiological action of PG is complex, and it is thought to regulate the functions of biological tissues such as the cardiovascular system, digestive tract, central nervous system, kidneys, platelets, endocrine organs, respiratory system, and female reproductive organs as a local hormone. A few specific examples are given below. [ I ] Prostaglandin _E2 . ( 5Z ,11α, 13E , 15S )-11,15-dihydroxy-9-oxoprosta-5,13-diene-1-oic _{acid. C20H32O5 (} 352.46) _. Abbreviated as _PGE2 . It is biosynthesized from arachidonic acid via an endoperoxide and is widely distributed in biological tissues. It is also synthesized from _PGF2α in more than 10 steps starting from cyclopentadiene. Colorless crystals. Melting point 65-66°C, -61.0° (THF). Easily soluble in methanol and ethanol. Easily dehydrated at pH 4 or below or pH 8 or above. Known effects include vasodilator, gastric secretion inhibitor, intestinal motility enhancer, uterine contraction, diuretic, bronchodilator, bone resorption, and immunosuppressant. Labor-inducing agent. [CAS 363-24-6] [ II ] Prostaglandin F _{2 α} . (5 Z ,9α,11α,13 E ,15 S )-9,11,15-trihydroxyprosta-5,13-diene-1-oic acid. C ₂₀ H ₃₄ O ₅ (354.47). Abbreviated as PGF _{2 α} . Synthesized or biosynthesized in the same way as PGE _2. Melting point 25-35°C. +23.9° (THF). Easily soluble in ethanol, ethyl acetate, and chloroform, poorly soluble in water. Stable for 2 years at 5-15°C, protected from light. It decomposes in one week when exposed to sunlight, and in three months even at 40°C. It is known to have effects such as vasoconstriction, increased intestinal motility, uterine contraction, bronchoconstriction, and luteal regression. [CAS 551-11-1] [ III ] Prostaglandin I _2. ( 5Z ,9α,11α, 13E , 15S )-6,9-epoxy-11,15-dihydroxyprostce-5,13-dien-1-oic acid _{. C20H32O5} (352.46). Abbreviated _{as PGI2} . Also known as prostacyclin. The epoxy moiety is unstable, so it is usually synthesized and isolated as the sodium salt. White powder. Melting point 166-168°C, or 116-124°C. +88° (chloroform). It is more stable than thromboxane _A2 , but its half-life is 20 minutes at 20°C in a pH 7.6 buffer solution, less than 10 minutes at 37°C, and inactivated within 15 seconds in boiling water. Its pharmacological action is the opposite of that of thromboxane _A2 , inhibiting platelet aggregation and lowering blood pressure. It is used to prevent blood coagulation during extracorporeal circulation in patients undergoing dialysis. [CAS 35121-78-9]

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

略称PG．1個の五員環をもつ，炭素数20のモノカルボン酸で生体内に広く分布していて多様な生理活性を示す物質の総称．研究の発端は，1930年，P. KurzockとC.C. Liebが人間の精液に子宮筋を収縮あるいは弛緩させる作用があるのを見いだしたことにあり，U.S. von Eulerらが，有機溶媒に可溶の有機酸成分を分離してプロスタグランジンと命名した．これらは，生体内でアラキドン酸やエイコサペンタエン酸が酸化的に五員環形成したプロスタン酸の基本骨格をもち，五員環部分の酸素原子と二重結合の違いによりA～Jの各群が区別され，また，側鎖の二重結合の数によって1～3群があり，これらを組み合わせて，PGE，PGF₂などと表記される．さらに，9位にヒドロキシ基をもつ場合には，その立体をα，βで区別するので約20種類が知られている．PGの生理作用は複雑であり，心臓血管系，消化管，中枢神経，腎臓，血小板，内分泌器官，呼吸系，女性生殖器などの生体組織の機能を局所ホルモンとして調節していると考えられている．以下に2，3の具体例を示す．【Ⅰ】プロスタグランジン E₂．(5Z,11α,13E,15S)-11,15-dihydroxy-9-oxoprosta-5,13-diene-1-oic acid．C₂₀H₃₂O₅(352.46)．略称PGE₂．アラキドン酸よりエンドペルオキシドを経て生合成され，生体内組織に広く分布している．シクロペンタジエンを出発物質として10数行程で，また，PGF_2αからも合成されている．無色の結晶．融点65～66 ℃，－61.0°(THF)．メタノール，エタノールに易溶．pH 4以下または pH 8以上で容易に脱水される．血管拡張，胃液分泌抑制，腸管運動亢進，子宮収縮，利尿，気管支拡張，骨吸収，免疫抑制などの作用が知られている．分娩誘発剤．[CAS 363-24-6]【Ⅱ】プロスタグランジン F_2α．(5Z,9α,11α,13E,15S)-9,11,15-trihydroxyprosta-5,13-diene-1-oic acid．C₂₀H₃₄O₅(354.47)．略称PGF_2α．PGE₂と同様に合成あるいは生合成される．融点25～35 ℃．＋23.9°(THF)．エタノール，酢酸エチル，クロロホルムに易溶，水に難溶．5～15 ℃ の遮光下で2年間は安定である．日光に当てると1週間で分解し，40 ℃ でも3か月で分解する．血管収縮，腸管運動亢進，子宮収縮，気管支収縮，黄体退行などの作用が知られている．[CAS 551-11-1]【Ⅲ】プロスタグランジン I₂．(5Z,9α,11α,13E,15S)-6,9-epoxy-11,15-dihydroxyprostce-5,13-dien-1-oic acid．C₂₀H₃₂O₅(352.46)．略称PGI₂．プロスタサイクリンともよばれる．エポキシ部分が不安定で，通常，ナトリウム塩として合成，単離される．白色の粉末．融点166～168 ℃，または116～124 ℃．＋88°(クロロホルム)．トロンボキサン A₂ よりは安定であるが，半減期は pH 7.6の緩衝液中20 ℃ で20 min，37 ℃ で10 min 以内，沸騰水中では15 s 以内で失活する．薬理作用はトロンボキサン A₂ とは正反対であり，血小板凝集阻害，血圧降下作用がある．人工透析患者の体外循環時の血液凝固防止に用いられている．[CAS 35121-78-9]

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